Good point, though you probably need a strong flow for turbines, which will be an issue for the bubble barrier. And for large rivers that are also deep (i.e. an

Good point, though you probably need a strong flow for turbines, which will be an issue for the bubble barrier. And for large rivers that are also deep (i.e. any river that is used for larger scale shipping), the infrastructure seems extreme. It's one thing to handle a 10m wide canal that's 2m deep, it's quite another to install that system on a river that's 800m across and 10m deep. I believe we'll quickly reach a level where it's not economical to do put a lot of energy into it to catch what little waste there is. On the other hand, maybe there are positive side effects, more oxygen in the water?